SaveYourself.ca • Sensible advice for aches, pains & injuries
Ice packs and heating pads are familiar rehabilitation tools, but many people have never heard of therapeutic contrasting: quickly changing tissue temperature from hot to cold and back again. This is usually achieved with hot and cold water, either dunking a limb or even immersing the whole body. The technique is most familiar to serious athletes, who believe — without much justification — that it helps them get back in the game quicker.
For injury recovery, contrasting is a good, cheap, safe, and simple idea, and I promise that it feels better than it sounds, when it’s done right. The point is to force your tissues to adapt to the sudden changes, which is stimulatory and requires a lot of metabolic activity and circulatory gymnastics. Basically, contrasting constitutes an extremely gentle tissue workout: stimulation without stress, and strong sensations without movement, which can be particularly helpful for a body part that badly needs some rest while it heals.
Contrasting probably has minor benefits, but it’s certainly not going to work any miracles. There is no reason to believe that contrasting would make a large difference in healing. In particular, it will probably not meaningfully “accelerate healing” from tissue traumas like sprains and strains.
What does the science say? Not much, unfortunately — just a handful of studies, mostly about athletic recovery, and mostly notable for failing to turn up anything promising.1 If contrasting promotes recovery from exercise, it can’t be much. That fits a general pattern: nothing seems to help with recovery from exercise, I’m afraid. For more about that, see my article about delayed-onset muscle soreness — this article focusses on contrasting for recovery from injury, which is definitely unproven, but more reasonable and plausible, costs nothing, and almost perfectly risk-free. But …
Limb contrasting is extremely safe in general, and what little danger there is can be avoided with an ounce of common sense. Don’t burn yourself. 
Please avoid contrasting the freshest injuries that are still hot, swollen, and/or red, because the heat may aggravate the inflammation more than the cooling phase can control. You should use just ice on a fresh injury (note an important exception: back pain should not be iced, because it is usually not an “injury” per se). Wait about three days for an injury like an ankle sprain to calm down a bit before you start contrasting it.
With rapid changes in circulation, there is some risk of getting dizzy or fainting. This is unlikely when you’re working just with limbs, but be aware of the possibility. Full body contrasting is a different matter. See below.
The rationales for contrasting, icing and heating are all nearly identical. Normal icing and heating are simply mild forms of contrasting, because you alternate between applying the ice or the heat and then removing it to let the tissues warm up or cool down. Contrasting just exaggerates this — so it is a refinement and/or hybrid of icing and heating. For instance, where anatomically practical, you could contrast by switching between ice and hot water, or a heating pack and ice water … and so on.
In contrast, contrasting some other anatomy is inconvenient to the point of pointlessness.
Although contrasting is so closely related to icing and heating, it does have a couple of noteworthy advantages.
First, icing can be irritating to muscles and/or the nervous system. Like heat, contrasting is usually more soothing, but it’s also more “balanced” — it’s pleasant to cool off after heating, and pleasant to warm up after cooling.
Second, it is possible to create a literally bigger effect with contrasting. It is hard to ice your entire forearm or calf. It is quite easy to dunk them. By immersing a much larger section of your body, you can make more of a splash. Literally and figuratively.
Experimenting with contrasting should be standard part of rehab from many musculoskeletal injuries, but especially repetitive strain injuries in the extremities. Repetitive strain injuries often need far more rest to recover from than people realize, and any technique for stimulating tissue without stressing it is valuable. Contrasting is also much easier and more practical and effective to apply to the limbs, so the best common candidates for contrasting are:
Knees are a little trickier, but still easy enough to contrast with a little creativity, so two more good candidates are the runner’s knee conditions, iliotibial band syndrome and patellofemoral syndrome.
Hips and shoulders are much more awkward to contrast, and also broader, thicker, and often more padded with fat, so it is harder to change their temperature. The hip joint itself is probably almost completely immune to contrasting, for instance, so there is almost no point in contrasting hip problems. Of course, contrasting is even less convenient or worthwhile for trunk trouble, like back pain.
Ligament sprains are very slow healing, and often become chronically painful, long after it seems like they should have healed. Although it’s doubtful that contrasting will “accelerate healing” from a sprain, it may be worth doing it anyway — after the initial swelling has died down — for the hope of some minor benefits.
There are many ways to heat up and cool your body parts, and I encourage you to use your imagination and all the tools at your disposal. Bear in mind that immersion is always better than a flow or spray: whenever possible, you want to surround the body part. The major delivery systems for temperature are:
Contrasting should follow the following basic pattern: three to six alternations between heating and cooling. More is probably getting to be a waste of time. Less than three is probably not worth bothering with either. (More on dosing below.)
Cold sounds nasty to a lot of people, but you’ll be surprised at how tolerable it is when you’re properly pre-warmed. In fact, if you’re hot enough, you can tolerate a great deal of cold — it’s one of the neat things about contrasting. The cold should feel frefreshing or “bracing” at the worst. If you think the cold is too intense, tweak the procedure: more time heating, less time cooling, and reduce the contrast.
Here are a whole bunch of specific examples and suggestions for using the best delivery systems for different body parts. Obviously, not every possible solution is covered here. I don’t think I’ve ever looked at this list without thinking, “Oh yeah, and there’s also __.” Be creative.
To some extent you can contrast in the shower. Whole body contrasting is nice and probably healthful in some general ways, but has limited value for rehabilitating from injuries, which require more intense temperatures, more accurately applied. Immersion of the body part is always the best. Intense heating of only the arm by dipping it in hot water, for instance, tends to cause much greater capillary dilation in the arm than the hottest shower.
The hottest and coldest showers are generally just too hot and too cold to tolerate on large areas of your body … or even just from the splashing if your trying to spray just one part of your body.
A detachable shower head, however, allows you to focus the spray enough to achieve a reasonably good effect.
Precision with dosage of contrasting is not particularly important. Heat and cool in roughly one-minute doses. But if you stick to the idea of “make it good and hot, and then make it good and cold” you’re doing it right.
And how many times should you cycle between hot and cold? Just a single time — one dose of hot, one dose of cold — is a minimal help. Three times is much more of a help, and is probably a good number. Six times is just tedious! There are practical considerations.
And how many times per day? Roughly once per day. More would undoubtedly be better — perhaps three times per day, for a few days, for a situation where contrasting is particularly easy and ideal for the injury — but there are usually strict practical limits on how much contrasting people can do, or should do.
It’s helpful, but it’s not so good that you should be spending half your day doing it!
This may be powerful medicine in some situations: don’t underestimate its usefulness just because it sounds a bit odd! Try it, have fun, enjoy the sensations, and you may find it more effective at helping you heal than medications or therapy.
Another interesting application of contrasting is the “thermal workout.” Full body contrasting — switching back and forth between hot tub and pool, for instance — can be surprisingly exhausting and physiologically potent.
It can even be dangerous, so for pity’s sake be careful and use some common sense:
Seriously, do not even think about trying this without going slow and taking it easy. This is one of those ideas that desperately needs a medical disclaimer! If you get into trouble doing this, it’s not because I didn’t warn you! Those warnings you see around public hot tubs and saunas? They are not for nothing!
Okay, I hope that’s enough ranting about the dangers to fully cover my butt.
Done safely, even a gentle thermal workout is ideal for wearing yourself out and burning some calories without straining anatomy, and that’s can be a handy component of a rehabilitation or general fitness regimen.
For instance, I often cluster workouts as close together as I dare. If I play competitive sports on Tuesday night, I may be pretty sore the next day and just barely have time for my body to recover for my next strength training workout on Friday. And yet I don’t want to be a lazy butt for three solid days. A thermal workout is a perfect way to poop myself out a bit without loading my tissues up with more stress than they can adapt to.
February 16, 2012 — Major revision and upgrade. Almost everything improved
June 6, 2011 — Added section, “The thermal workout.”
March 18, 2010 — Added reference to Hing.
This review of the science of contrast hydrotherapy concludes that there is no science of contrast hydrotherapy: no research has ever been done that provides useful evidence that it works or does not work. Contrasting remains a popular and plausible but untested form of treatment.
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